The stepping motor is used, for example, with a sewing machine in order to adjust needle swinging amplitude or fabric feed. The stepping motor is often given external force intentionally or incidentially, shocks during transportation or reaction of a stator effected with stepping movement with respect to movement of a rotor shaft while driving the stepping motor. For measures to those matters, a first requirement is to reduce lag in a center of the rotor shaft, and a second requirement is to reduce noises caused by driving the stepping motor. However, it is generally difficult to satisfy the first and second requirements at the same time. If the stepping motor were rigidly held to the machine housing through an attaching plate, the first requirement would be satisfied, but the second requirement could not be satisfied, since action of the rotor shaft generates reaction of the stator during operation of the stepping motor and makes considerable noises.
On the contrary, if the stepping motor were elastically held to the attaching plate fixed to the machine housing via a plurality of elastic members, the second requirement could be satisfied, but compression rates of said elastic members would be much more sporadic if tolerance between cores of opposing members were not exactly observed, and the above mentioned disadvantages would be caused.